16
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Piping installation
Installer and user reference guide
80
LRYELRNUN5A7Y1
CO₂ Conveni-Pack outdoor unit
4P605460-1 – 2020.08
B
Stop valve (liquid – refrigeration)
a
Gas piping
b
Liquid piping
3
If applicable, connect the piping to the capacity up unit.
16.3.5 To braze the pipe end
General guidelines
▪
When brazing, blow through with nitrogen to prevent creation of large quantities
of oxidized film on the inside of the piping. This film adversely affects valves and
compressors in the refrigerating system and prevents proper operation.
▪
Set the nitrogen pressure to 20 kPa (0.2 bar) (just enough so it can be felt on the
skin) with a pressure-reducing valve.
a
b
c
d
e
f
f
a
Refrigerant piping
b
Part to be brazed
c
Taping
d
Manual valve
e
Pressure-reducing valve
f
Nitrogen
▪
Do NOT use anti-oxidants when brazing pipe joints.
Residue can clog pipes and break equipment.
▪
Do NOT use flux when brazing copper-to-copper refrigerant piping. Use phosphor
copper brazing filler alloy (CuP279, CuP281, or CuP284:DIN EN ISO 17672), which
does not require flux.
Flux has an extremely harmful influence on refrigerant piping systems. E.g., if a
chlorine-based flux is used, it will cause pipe corrosion or, in particular, if the flux
contains fluorine, it will deteriorate the refrigerant oil.
▪
Always protect the surrounding surfaces (e.g. using insulation foam) against heat
when brazing.
Preheating the piping
a
b
c
a
Correct heating zone
b
Heating zone is too large. Brazing material can cause obstructions inside the piping. A running test might
detect these obstructions.
c
Heating zone is too small. The brazed connection will not be strong and might rip.
a
c
b
5 mm
80~85
˚
3 mm
